Day: January 24, 2014

[Marin Davide] was on a mission. A mission to build his own curved display screen, using an Arduino, nichrome wire, and thermochromic liquid crystal ink.

The prototype he’s designed uses a sheet of plastic coated in thermochromic ink, curved on an MDF frame. This particular thermochromic ink turns bright blue when heated to around 27°C.

To display digits, he’s created tiny segments of the 7-segment display by wrapping the nichrome wire around pieces of cardboard, which then have been glued to the back of the display. Each of these is controlled separately from his Arduino Mega. He muses that you could also make a rudimentary dot matrix display with this — it would be interesting to see what kind of resolution you could obtain!

To see more photos check out the original DesignNews post linked above. We’re not sure why the bulk of the details are only available in this PDF. If we’re just missing a direct link to the original project page let us know in the comments and we’ll update the post.

The HackPhx Winter 2014 hackathon was held at Heatsync Labs hackerspace in Mesa, Arizona, USA. The advertised theme was “Arduino Wearables”. Participating attendees were randomly placed on teams evenly distributed by their disclosed skills across all teams. There were 10 teams with 4 to 5 members per team competing for two winning spots.

Top prize was the Judges’ prizes for the best completed and documented Xadow wearable team project. The second prize was the Jury’s prize given to the team project that the other teams liked the most regardless of event criteria.

Read more about the winning teams and watch their presentations after the break.

Developed in the very late 60s and through the 70s, the PDP-11 series of minicomputers was quite possibly the single most important computer ever created. The first widely distributed versions of Unix and C were developed on the PDP-11, and it’s hardware influence can be found in everything from the Motorola 68000 to the MSP430.

When [Dave Cheney] saw the recent 8086 simulator written in 4kB of C code, he realized simulating entire computer systems doesn’t actually require a whole lot of resources outside a big chunk of memory. Armed with an Arduino Mega clone, he set out on one of the coolest projects we’ve seen in a while: simulating a PDP-11 on an AVR.

[Dave] used an ATMega2560-powered Arduino Mega clone with an Ethernet module for the hardware of this build. Attached to it is a shield filled up with a pair of RAM chips that expand relatively limited amount of RAM on the ‘Mega.

So far, [Dave] has his simulated system booting Unix V6 off an SD card. For PDP-11 storage, he’s also simulating an RK05 disk drive, a massive 14 inch platter containing 2.5 Megabytes of data. Compared to the original PDP-11/40, [Dave] estimates his machine is about 10 times slower. Still, an original 11/40 system fills multiple server racks, and the most common installations consume several kilowatts of power. The Arduino Mega can fit in a pocket and can be powered over USB.

Future developments for this system include improving the accuracy of the simulator, running more advanced operating systems and the DEC diagnostic programs, and possibly speeding up the simulation. We’d suggest adding some switches and blinkenlights on an additional shield, but that’s just us.

All the code can be found on [Dave]’s git, with a description of his SPI RAM shield coming shortly.

There are some big hackerspaces out there.
And then there’s The Geek Group.
It takes a certain chutzpah to convert a 43,000 foot former YMCA into a hackerspace. And an epic hackerspace it is, complete with 5 axis CNC machines, 3d printers, and of course, giant robots romping through a forest of Tesla coils. The Geek Group has performed live demos in front of thousands of people over the years, and inspired tens of thousands more via the internet. You don’t work this big without having some big adventures, and The Geek Group is no exception. They’ve been through roof leaks, gas pipe breaks, surprise tax bills and angry neighbors. They’ve also been dealing with their current adventure, fire.

Unless you’ve been under a rock the last few weeks, you’ve probably read about the recent fire, and ensuing cleanup at The Geek Group labs. We’ve covered the fire and its cause here on Hackaday, with no small amount of drama in our comments section. There is a small but vocal minority who don’t have many good things to say. Accusations of cults, safety violations, and tax evasion often fly. While some groups would take this lying down, the geek group put on their flame proof suits and wade through the comments. None more vocally than [Chris Boden], the president, CEO and founder.

DISCLAIMER: The interview contains questionable content and some profanity (which we’ve altered as grawlix). We have posted the transcript as it was captured, which includes some spelling and grammar issues. Please consider these things before clicking through to the interview itself.

For a university project [Adam Libert] decided to make his very own parabolic hot dog cooker. Now, we must say, this is a project that could probably be cobbled together in a weekend from scraps, but since it was for a lab, [Adam] decided to go all out — complete with a perfect laser cut frame.

The objective of the lab was to design a project that can use solar radiation to accomplish a task, and being partial to hot dogs, the hot dog cooker was a natural choice. He designed the parabolic mirror to focus 1/5th of a square meter of sunlight directly at a hot dog. To do this, he laser cut the frame out of MDF, and using tinfoil, toothpicks, and poster paper, assembled the mirror. The whole thing cost less than $5 (ignoring laser time) and can be setup in a matter of minutes.

He determined the heat output of the cooker to be around 10W at the hot dog, which means he was able to bring the hot dog to 150°F in about 10 minutes — which was surprisingly close to his original calculations, because let’s face it, tin foil is hardly an ideal mirror.

The dongles are based on the ATMega88PA and work on three levels to provide something for everyone. The no-experience-necessary option is to plug it in to a USB port and admire the light show sequences. If you know enough to be dangerous, you can remotely control the LEDs from a USB host using [kiu]’s sldtool for Linux or Mac. He originally included examples that visualize CPU utilization and ultimately added a Ruby-based departure countdown for the next outbound train at the nearby station.

If you’re 1337 enough you can flash your own C or assembly code via USB. Holding down the button during power-up lets you use the dongle as a USBasp so it can be flashed with avrdude. [kiu] says the bootloader can’t be unlocked through software and is theoretically unbrickable. Stick around after the break to see the full demo.

Have you ever found the need to make your own wooden balls for a project? To be frank, we haven’t either! But seriously — how would you do it? Well, lucky for us, Hackaday Alum [Jeremy Cook] has experimented with a few different methods.

He was originally inspired by this video from [Philip Stephens] who makes them completely by hand using a hand-made hole saw. Not wanting to spend hours making a ball, he thought about ways to automate it — well, kind of.

His first attempt was to use a mill and a rudimentary rotary index table consisting of a wood clamp — Hold a wooden dowel in place, hole saw halfway through, rotate in the clamp, repeat times infinity. Eventually you’ll be left with a wooden ball whose sharp edges you can just break off. Not very satisfied with this method, he discovered a Reddit thread on making wooden balls with a rather ingenious method… Stick around after the break to see how.